/*
 * Alloy Analyzer
 * Copyright (c) 2002 Massachusetts Institute of Technology
 *
 * The Alloy Analyzer is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * The Alloy Analyzer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with the Alloy Analyzer; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package alloy.util;

import java.util.HashMap;
import java.util.Map;

/**
 * A canonicalizer for objects.
 */
public class Canonicalizer {
    /** {@link Map} from {@link Object} to its canonical representative (itself). */
    Map /* Object->Object */ _canonMap = new HashMap();

    /** Return a canonical copy of the object. */
    public Object canon(Object obj_) {
	Object canonObj = _canonMap.get(obj_);
	if (canonObj == null)
	    _canonMap.put(obj_, canonObj = obj_);
	return canonObj;
    }
}
